[TenTec] Omni VI+ Keying

[Michael Tope]

----- Original Message ----- 
From: "Ken Brown" <ken.d.brown at verizon.net>

> Hi Michael,
>
> I don't know what version firmware is in my Omni VI version 3 radio.
> Maybe it has the "microchirp". No one has complained about it to me.
> I'll try listening to it with another receiver to see whether I can
> detect a chirp, and I'll also try listening to harmonics to exaggerate
> the chirp.

I talked to a friend last night who also has an Omni 6+. He said
that he couldn't hear any "microchirp" on his Omni 6+, so I dunno
what my problem is. During the one test I did, I could definitely hear
it, but I don't find it bothersome (at least not on the fundamental).
BTW, I checked the label on the logic ROM. It says V1.03.

> As for as the duty cycle goes, I am seeing pretty darned near
> 50% duty cycle when the internal keyer speed is at maximum. Gives a dit
> plus space duration of about 43 mS. The dits are 20 to 24 mS long
> depending on what part of the envelope you call the end of the dit. The
> rise time of the dit envelope is about 2 mS and the fall time is about 4 
> mS.
>
> I see pretty much the same using external keying from my Logikeyer K-3,
> although they way I have it set up right now it does not go as fast as
> the internal keyer.
>
> Do you have a number I can use to convert dit plus space duration
> directly to WPM?

If found some derivations on the internet that suggest that WPM = 2.4
X the dit frequency. The specs on INRAD website say 50ms pulse rep
rate = 48 WPM, which would be consistent with that number (1/50ms
x 2.4 WPM/Hz = 48 WPM). Assuming the above is correct, a 43ms
dit plus space duration would be about 56 WPM, so it sounds like
your Omni 6 is working okay at up to at least 56 WPM. My AEA
MorseMachine will do something like 99WPM when you crank
it all the way up, so I will give that a try when I get a chance.

>
> When I look at it with the Bird 43 and set the power to 90 watts key
> down (I can't quite get 100 watts indicated, so I am turning it down to
> 90 watts) the string of dits measures 30 watts. The Bird 43 scale is not
> linear, so this is about 50% deflection even though not 50% power reading.
>

It just occured to me that the MorseMachine toggles between
the speed knob pot (what I normally use) and the keypad set
speed, so I can probably set the keypad speed to a known
calibrated speed/duty cycle and then just toggle over to it when
tuning with the Omni 6+ in lieu of using the faster Inrad Key
Pulser.

73 de Mike, W4EF.............................

> DE N6KB
>
>
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